Field
This disclosure relates to negative active materials, negative electrodes and lithium batteries including the same, and methods of manufacturing the negative active materials.
Description of the Related Technology
Lithium secondary batteries used in portable electronic devices for information communication, such as personal digital assistants (PDAs), mobile phones, or notebook computers, electric bicycles, electric vehicles, or the like have a discharge voltage that is at least twice as high as that of a conventional battery, and thus, have high energy density.
Lithium secondary batteries generate electric energy by oxidation and reduction reactions occurring when lithium ions are intercalated/deintercalated into/from a positive electrode and a negative electrode with an organic electrolytic solution or a polymer electrolytic solution interposed between the positive and negative electrodes, each electrode including an active material that enables intercalation and deintercalation of lithium ions.
Research on various forms of carbonaceous materials such as synthetic and natural graphite, and hard carbon, which are capable of intercalation/deintercalation of lithium, and non-carbonaceous materials such as Si is of interest.
When a negative electrode material of a lithium secondary battery directly contacts an electrolyte, the electrolyte may undergo reductive cleavage at a low electric potential. Accordingly, the negative electrode material and the electrolyte of the lithium secondary battery may have increased reactively to form a thin film on a surface of the negative electrode at a low electric potential. In this regard, the higher the temperature of the battery, the greater the reactivity between the negative electrode material and the electrolyte. Due to the thin film, lithium ions and electrons are consumed, thereby deteriorating lifespan characteristics of the lithium secondary battery.
Accordingly, there is a need to develop a negative active material having improved lifespan characteristics.